1. Field of the Invention
This invention relates to cold head sleeve and High-Tc superconducting lead assemblies for use in superconducting magnets. Such structures of this type, generally, provide the proper cold head and superconducting lead characteristics for a superconducting magnet which has a small imaging volume.
2. Description of the Related Art
A variety of cold head sleeve and current lead assemblies have been built and used in conduction-cooled magnetic resonance (MR) imaging magnet systems. Exemplary of such prior art cold head sleeve and current lead assemblies, achieving a modicum of success in this regard are: U.S. Pat. No. 4,895,831, entitled "Ceramic Superconductor Cryogenic Current Lead" to E.T. Laskaris; U.S. Pat. No. 4,926,647, entitled "Cryogenic Precooler and Cryocooler Cold Head Interface Receptacle" to Dorri et al.; and U.S. Pat. No. 4,930,318, entitled "Cryocooler Cold Head Interface Receptacle" to S. J. Brzozowski, all three of which are assigned to the same assignee as the present invention.
As can be seen in the Laskaris patent, the superconducting lead assembly is used in a large, whole body MR imaging system, Consequently, these leads do not provide a compact, low cost design. With respect to the Dorri et al. and Brzozowski patents, the cold heads disclosed in these patents are also used in large, whole body MR imaging systems. Therefore, they would not be capable of providing a low-cost, compact design needed for a superconducting magnet which is used only to image human limbs. A more advantageous cold head sleeve and superconducting lead assemblies, then, would be presented if the cold head sleeve and superconducting lead assemblies were more compact and lower in cost.
It is apparent from the above that there exists a need in the art for a cold head sleeve and High-Tc superconducting lead assembly which is light weight and compact through simplicity of parts and uniqueness of structure, and which at least equals the operation characteristics of the known cold head sleeve and superconducting lead assemblies, particularly those of the highly advantageous type disclosed in the above-referenced Laskaris, Dorri et al. and Brzozowski patents, but which at the same time is capable of providing the performance required by a superconducting magnet that is used only to image human limbs. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.